1. Field of the Invention
The present invention relates to an outlet structure of sealed container, and more particularly to an outlet structure of chip tube for exhaust in a sealed container such as a plasma display panel, and a technique for manufacturing the same.
2. Description of the Background Art
FIG. 18 is a cross section showing a principal part of an outlet structure of sealed container in accordance with a first prior art illustrated in FIG. 3 of microfilmed Utility Model Application No. 61-73604. FIG. 18 shows a sealed container body 10A constituted of two glass substrates such as a plasma display panel whose peripheral portions are bonded to retain an airtight condition, a second substrate 1011A made of glass which is a constituent of the sealed container body 10A, such as a rear glass substrate opposed to a display surface side in a case of a plasma display panel, an exhaust hole 1012A, a concave portion 1013A provided in an outer surface side of the second substrate 1011A, a chip tube 20A as a hollow member for exhaust to be connected to a not-shown vacuum pump and the like when the sealed container body 10A is exhausted and a glass paste 30A obtained by mixing powder of low melting point glass (frit glass) as a thermofusible material into a binder and the like. In the following discussion, the low melting point glass refers to a glass material having a melting point lower than that of normal glass, e.g., of about 400xc2x0 C., more broadly to a glass material which is melted in a temperature lower than the above sealed container body 10A and the chip tube 20A are melted.
A prior-art process for bonding the chip tube 20A for exhaust to the sealed container body 10A goes as follows. As shown in FIG. 18, the chip tube 20A is inserted in the exhaust hole 1012A having the concave portion 1013A provided in the second substrate 1011A of the sealed container body 10A, to be stood. After applying the glass paste 30A by hand-painting and the like, the chip tube 20A is put in a furnace, being stood, together with the sealed container body 10A, to be heated. The glass paste 30A is melted, to thereby bond (seal) the second substrate 1011A and the chip tube 20A.
FIG. 19 is a vertical cross section showing an outlet structure of sealed container in accordance with a second prior art illustrated in FIG. 4 of microfilmed Utility Model Application No. 61-73604. In the structure of FIG. 19, the chip tube 20B consisting of a tubular portion 2021 and a flare portion 2022 covers an exhaust hole 1012B provided in a lower plate 1011B of a sealed container 10B. A process for bonding the chip tube 20B and the lower plate 1011B of the sealed container 10B goes as follows. Specifically, a sealing member 30B in paste form such as frit glass is applied to the periphery of an outer rim of the flare portion 2022, a portion of an outer surface thereof and a portion of an inner surface thereof by hand, and the whole device is thereafter heated to seal the lower plate 1011B and the chip tube 20B.
When the prior-art method, i.e., hand-painting of glass paste, is used, the thickness of applied glass paste is likely to be uneven and it is difficult to apply the glass paste steadily to the same position, it sometimes happens that the glass paste is applied to unnecessary portions. If the glass paste is applied to an unnecessary portion, melted low melting point glass flows in the sealed container body through the exhaust hole to contaminate the inside of the sealed container body. Further, if bubbles are mixed in the applied glass paste, the physical strength is deteriorated and at worst a leak occurs to break the airtight condition.
The present invention is directed to an outlet structure of sealed container. According to a first aspect of the present invention, the outlet structure of sealed container comprises: a hollow member having a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member, the one end portion being in contact with a major surface of a sealed container body on the periphery of a hole provided in the sealed container body, the opening portion and the tubular portion covering the hole, the hole and the tubular portion having center axes which substantially coincide with each other; and a sealing member adhered contiguously from the outside of an outer rim of the flare-shaped opening portion at the one end portion of the hollow member in the major surface to a portion of the tubular portion beyond the boundary of the flare-shaped opening portion and the tubular portion over the major surface between the outer rim and the outside of the outer rim and a surface of the opening portion.
According to a second aspect of the present invention, in the outlet structure of sealed container of the first aspect, low melting point glass is used as a base material of the sealing member.
According to a third aspect of the present invention, in the outlet structure of sealed container of the second aspect, the sealing member is formed by melting the low melting point glass after disposing the low melting point glass on the periphery of the hollow member.
According to a fourth aspect of the present invention, in the outlet structure of sealed container of the third aspect, the low melting point glass is formed in a tubular shape.
According to a fifth aspect of the present invention, in the outlet structure of sealed container of the fourth aspect, the inside of one end portion of the low melting point glass is out of contact with the flare-shaped opening portion and abuts the major surface of the sealed container body.
According to a sixth aspect of the present invention, in the outlet structure of sealed container of the fourth aspect, the inside of one end portion of the low melting point glass has a concave portion with a diameter substantially equal to a diameter of the outer rim of the flare-shaped opening portion.
According to a seventh aspect of the present invention, in the outlet structure of sealed container of the fourth aspect, the low melting point glass has an outer diameter which is one point two to one point four times as large as a diameter of the outer rim of the flare-shaped opening portion.
According to an eighth aspect of the present invention, in the outlet structure of sealed container of the first aspect, the sealed container body is provided with a holding portion which holds at least a portion of the outer rim of the flare opening portion.
According to a ninth aspect of the present invention, in the outlet structure of sealed container of the first aspect, the sealed container body corresponds to a plasma display panel body.
According to a tenth aspect of the present invention, in the outlet structure of sealed container of the first aspect, the sealed container body corresponds to a display unit body for displaying an image.
According to an eleventh aspect of the present invention, the outlet structure of sealed container comprises: (a) a hollow member having a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member, the one end portion being located above a major surface of a sealed container body on the periphery of a hole provided in the sealed container body, the opening portion and the tubular portion covering the hole, the hole and the tubular portion having center axes which substantially coincide with each other; and (b) a sealing member adhered on the one end portion of the hollow member to fill between the one end portion and the major surface.
According to a twelfth aspect of the present invention, in the outlet structure of sealed container of the eleventh aspect, low melting point glass is used as a base material of the sealing member.
According to a thirteenth aspect of the present invention, in the outlet structure of sealed container of the twelfth aspect, the sealing member is formed by disposing a press frit which is press molded in a tubular form in advance on the major surface on the periphery of the hole, melting the press frit after disposing the one end portion of the hollow member thereon and thereafter cooling melted press frit.
According to a fourteenth aspect of the present invention, in the outlet structure of sealed container of the eleventh aspect, the sealed container body corresponds to a plasma display panel body.
According to a fifteenth aspect of the present invention, in the outlet structure of sealed container of the eleventh aspect, the sealed container body corresponds to a display unit body for displaying an image.
The present invention is also directed to a method of forming an outlet structure of sealed container. According to a sixteenth aspect of the present invention, the method comprises the steps of: (a) preparing a sealed container body comprising a hole for exhaust formed inwardly from a major surface of said sealed container body; (b) preparing a hollow member having a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member; (c) preparing a thermofusible material which is produced in a tubular form, having an outer diameter larger than an outer diameter of the one end portion of the hollow member, an innermost diameter smaller than the outer diameter of the one end portion and larger than a diameter of the hole and a melting point lower than those of the hollow member and the sealed container body; (d) disposing the thermofusible material on the major surface on the periphery of the hole and disposing the one end portion on a surface of the thermofusible material so that center axes of the hollow member and the hole substantially coincide with each other; and (e) bonding the sealed container body and the one end portion of the hollow member to each other by heating and melting the thermofusible material.
According to a seventeenth aspect of the present invention, in the method of the sixteenth aspect, the step (d) comprises the steps of (d-i) preparing a jig comprising {circle around (1)} a stick member comprising a first portion with its maximum diameter being substantially equal to an inner diameter of the tubular portion and a second portion contiguous to one end of the first portion to serve as a tip portion with its maximum diameter being substantially equal to a diameter of the hole, {circle around (2)} a column having a top portion connected to the other end of the first portion of the stick member and a side plate portion with its upper portion connected to the top portion, the column supporting the stick member extending downwardly with the top portion, and {circle around (3)} a base portion having an upper surface portion connected to a lower portion of the side plate portion of the column and a lower surface portion which can come into contact with the major surface outside a position where the thermofusible material is disposed, the jig made of a material having a melting point higher than the thermofusible material, a length of the stick member being larger than a height from the top portion to the lower surface portion of the base portion; (d-ii) disposing the thermofusible material on the major surface on the periphery of the hole and thereafter disposing the one end portion of the hollow member on the surface of the thermofusible material; and (d-iii) inserting the stick member into a hollow portion of the hollow member to fit the first portion into the hollow portion and further inserting the second portion into the hole to provide the lower surface portion of the base portion on the major surface in contact with each other, and the step (e) comprising the step of (e-i) heating the thermofusible material together with the jig.
According to an eighteenth aspect of the present invention, in the method of the seventeenth aspect, the step (d-i) comprises the step of (d-i-1) preparing a cover having an inner diameter which is substantially equal to the maximum outer diameter of the first portion and an outer diameter larger than an outer diameter of the tubular portion, the step (d-ii) comprises the step of (d-ii-1) putting the cover on the other end portion of the hollow member disposed on the surface of the thermofusible material, and the step (d-iii) comprises the step of (d-iii-1) inserting the stick member into the hollow portion of the hollow member through a center hole of the cover.
The present invention further has the following aspects. According to an aspect of the present invention, a method of forming an outlet structure of sealed container comprises the steps of: (a) preparing a hollow member including a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member; (b) preparing a jig comprising {circle around (1)} a stick member including a first portion with its maximum diameter being substantially equal to an inner diameter of the tubular portion of the hollow member disposed on a sealed container body and a second portion contiguous to the first portion to form a tip portion with its maximum diameter being substantially equal to a diameter of a hole provided in the sealed container body, {circle around (2)} a column for supporting the stick member with its one end portion connected to the stick member, and {circle around (3)} a base portion having an upper surface portion connected to the other end portion of the column and a lower surface portion disposed on the sealed container body; (c) preparing a thermofusible material which is produced in such a tubular shape as to be accommodated in a space surrounded by the base portion, having an outer diameter larger than an outer diameter of the one end portion of the hollow member, an innermost diameter larger than an outer diameter of the tubular portion and smaller than the outer diameter of the one end portion and a melting point lower those of the hollow member, the jig and the sealed container body; (d) inserting the second portion of the stick member into the hole through the tubular portion and the flare-shaped opening portion after disposing the thermofusible material on the periphery of the hollow member to fit the first portion into the tubular portion and make the center axes of the hole and the hollow member coincident; and (e) bonding the sealed container body and the hollow member to each other by heating the thermofusible material together with the jig to melt the thermofusible material.
According to another aspect of the present invention, a plasma display panel comprises: a plasma display panel body; a hollow member including a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member, the one end portion being in contact with a major surface of the plasma display panel body on the periphery of a hole provided in the plasma display panel body, the opening portion and the tubular portion covering the hole, the hole and the tubular portion having center axes which substantially coincide with each other; and a sealing member adhered contiguously from the outside of an outer rim of the flare-shaped opening portion at the one end portion of the hollow member in the major surface to a portion of the tubular portion beyond the boundary of the flare-shaped opening portion and the tubular portion over the major surface between the outer rim and the outside of the outer rim and a surface of the opening portion.
According to a further aspect of the present invention, a method of manufacturing a plasma display panel comprises the steps of: (a) preparing a hollow member including a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member; (b) preparing a jig comprising {circle around (1)} a stick member including a first portion with its maximum diameter being substantially equal to an inner diameter of the tubular portion of the hollow member disposed on a plasma display panel body and a second portion contiguous to the first portion to form a tip portion with its maximum diameter being substantially equal to a diameter of a hole provided in the plasma display panel body, {circle around (2)} a column for supporting the stick member with its one end portion connected to the stick member, and {circle around (3)} a base portion having an upper surface portion connected to the other end portion of the column and a lower surface portion disposed on the plasma display panel body; (c) preparing a thermofusible material which is produced in such a tubular shape as to be accommodated in a space surrounded by the base portion, having an outer diameter larger than an outer diameter of the one end portion of the hollow member, an innermost diameter larger than an outer diameter of the tubular portion and smaller than the outer diameter of the one end portion and a melting point lower those of the hollow member, the jig and the plasma display panel body; (d) inserting the second portion of the stick member into the hole through the tubular portion and the flare-shaped opening portion after disposing the thermofusible material on the periphery of the hollow member to fit the first portion into the tubular portion and make the center axes of the hole and the hollow member coincident; and (e) bonding the plasma display panel body and the hollow member to each other by heating the thermofusible material together with the jig to melt the thermofusible material.
According to an yet aspect of the present invention, a display device comprises: a display portion body provided therein with an electrode for display; a hollow member having a tubular portion and a flare-shaped opening portion contiguous to the tubular portion with its diameter expanded towards one end portion of the hollow member, the one end portion being in contact with a major surface of the display portion body on the periphery of a hole provided in the display portion body, the opening portion and the tubular portion covering the hole, the hole and the tubular portion having center axes which substantially coincide with each other; and a sealing member adhered contiguously from the outside of an outer rim of the flare-shaped opening portion at the one end portion of the hollow member in the major surface to a portion of the tubular portion beyond the boundary of the flare-shaped opening portion and the tubular portion over the major surface between the outer rim and the outside of the outer rim and a surface of the opening portion.
Thus, the present invention produces the following effects.
In accordance with the outlet structure of sealed container of the first aspect, the airtight condition is kept and the bending strength is improved, to achieve an excellent outlet structure of sealed container.
In the outlet structure of sealed container of the second and twelfth aspects, the sealed container and the hollow member can be bonded while preventing deformation of the sealed container.
In the outlet structure of sealed container of the third aspect, it is possible to prevent the melted low melting point glass from flowing in the sealed container body.
In the outlet structure of sealed container of the fourth aspect, the sealed container and the hollow member can be reliably bonded and the low melting point glass can be easily adhered on the hollow member.
In the outlet structure of sealed container of the fifth aspect, the airtight condition is more reliably achieved.
In the outlet structure of sealed container of the sixth aspect, the low melting point glass can be disposed with high accuracy and the airtight condition is more reliably achieved.
In the outlet structure of sealed container of the seventh aspect, the bonding is made with more reliable airtight condition and higher bending strength.
In the outlet structure of sealed container of the eighth aspect, the airtight condition can be kept more reliably and the bending strength can be improved.
In accordance with the eleventh to eighteenth aspects of the present invention, {circle around (1)} the one end portion of the hollow member can be reliably bonded on the major surface with the sealing member without applying the glass paste by hand, and {circle around (2)} it is possible to prevent the stress from concentrating on the tubular portion of the hollow member and inhibit occurrence of cracking on the tubular portion in an exhausting process.
Especially, in accordance with the seventeenth aspect of the present invention, since a predetermined jig is used, the center axes of the hollow member and the hole can substantially coincide with each other with stability, reliability and ease and the positions of the thermofusible material and hollow member can be determined with stability and high accuracy, and moreover it is possible to stably keep substantial coincidence between the center axes of the hollow member and hole even in a state where the thermofusible material is melted.
Further, in accordance with the eighteenth aspect of the present invention, since the cover is used, it is possible to inhibit inhalation of unnecessary impurity gases into the sealed container body in the sealing process, especially during cooling.
In the method of forming the outlet structure of sealed container of the present invention, since the jig having the stick member which is inserted in the hole provided in the sealed container body and the hollow member to make the respective center axes substantially coincident is used and the thermofusible material which is formed in a tubular form on the periphery of the hollow member is heated and melted to bond the sealed container body and the hollow member, it is possible to make the center axes of the hole and the hollow member substantially coincident easily and stably. Moreover, it is possible to prevent the hollow member from falling down and stabilize the position of the hollow member.
In accordance with the plasma display panel of the present invention, an excellent plasma display panel is achieved with the airtight condition kept and the bending strength improved.
In accordance with the method of manufacturing the plasma display panel of the present invention, the method of manufacturing the plasma display panel is achieved, by which the respective center axes of the hole provided in the sealed container body and the hollow member can substantially coincide with each other easily and stably and it becomes possible to prevent the hollow member from falling down and stabilize the position of the hollow member.
In accordance with the display device of the present invention, a display device having a display portion with excellent display condition without contamination due to the melted sealing member inside the display portion. Further, a display device is achieved, which has high bending strength at the adhered member and causes no damage in the outlet structure of the display unit even if, for example, some external force is applied due to vibration in conveyance and the like.
An object of the present invention is to provide an outlet structure of sealed container which allows a sealed container body and a hollow member to be stably sealed.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.